RENEWABLE ENERGY RESOURCES

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RENEWABLE ENERGY RESOURCES

• FOSSIL FUELS, ELECTRICITY
• PAST PRESENT FUTURE

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Key Words

• Energy being able to do work. e.g. food gives
  us energy, so that we can move
• Fuel - Fuel is anything that is
• burned or altered to obtain energy

Fuel gauge
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Energy

• Some 2 billion people lack access to electricity
  and rely on traditional fuel sources such as
  firewood, kerosene, or biomass for their cooking
  and heating.

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Electricity
Generation Distribution

• Electricity generation fossil fuels and uranium
• Renewable energy is growing

(US Energy Information Administration, 2004)
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I. Fossil Fuels

• Petroleum
• Natural Gas
• Coal
• Oil Shale and Tar Sands
• CO2 Emissions

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Energy from fossil fuels

• Fossil fuels are coal, oil and gas
• Coal
  oil and gas
• Fossil fuels were formed from
• dead plants and animals over
• millions of years.

fossils
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Energy from fossil fuels

• Fossil fuels have formed over millions of years.
  Plants and animals died and were immediately
  covered by sediment in seas or swamps.
• After millions of years of pressure and heat
  (900C to 1200C), these remains turned into COAL,
  OIL and NATURAL GAS.
• Coal comes mainly from dead plants, like trees,
  falling into swamps.
• Oil and gas occur together and were formed from
  both plants and animals being buried.
• When we burn fossil fuels were using the suns
  energy that has been stored as chemical energy
  underground for millions of years.

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How fossil fuel power stations work

• Coal is crushed to a fine dust and burnt. Oil and
  gas can be burnt directly.

www.vauxhallsociety.org.uk
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Why use fossil fuels to make electricity?

• Advantages
• Electricity can be generated fairly cheaply.
• Transporting oil and gas to the power stations is
  easy.
• Gas-fired power stations are very efficient.
• A fossil-fuelled power station can be built
  almost anywhere.
•  
• Disadvantages
• Pollution. Burning any fossil fuel produces
  carbon dioxide, which contributes to the
  "greenhouse effect", warming the Earth.
• Burning coal produces more carbon dioxide than
  burning oil or gas.
• Mining coal can be difficult, dangerous and ugly.
• Coal-fired power stations need huge amounts of
  fuel.
• Fossil fuels are a non- renewable energy
  resource. Once we've burned them all, there
  isn't any more and our use of fossil fuels has
  nearly doubled every 20 years since 1900. This
  is a particular problem for oil, because we also
  use it to make plastics and many other products.

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World Greenhouse Gas Emissions
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hold down CO2

• The best way to hold down CO2 increases is to
  remove fossil fuels from electricity generation,
  but use it just for vehicles.
• Since ½ of US electricity comes from coal which
  generates twice as much CO2 per energy unit as
  does natural gas, we should switch to natural
  gas. This, however, involves massive and
  possibly costly imports.
• We need increases in alternate energy sources
  such as hydro, nuclear, wind and solar.
• We also need increases in energy efficiency and
  conservation.
• This especially includes high mileage vehicles.

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Carbon in Fuels Billions of tons of C
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Increasing Demands And Consequences

• Oil is extracted at the rate of 75 million
  barrels per day, which means the current reserves
  are predicted to last only for another 35-40
  years.
• The cost of oil has already increased so much

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COALThe energy bridge to the future!!

• First fossil fuel to be discovered.
• Pushed to background because of its environmental
  effects.
• The two major uses for coal steel production
  and electricity.
• Accounts for 23 of the global primary energy
  demand, 38 of world electricity production and
  70 of world steel production.

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• Major pollutants are volatile organic compounds
  (VOC), Nitrogen oxides (NOX), CO, SO2,
  particulate matter, mercury and lead.
• Electric utility power plants 72, 35, and 33
  of total emissions of SO2, CO2, and NOx.
• Average mercury content of coal is 7.4 pounds per
  trillion Btu of energy input to the coal-fired
  electricity generator.

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Reverting to COAL

• For coal to reestablish itself as the primary
  fuel, it will need to reduce its environmental
  footprint.
• Comparison of Air Pollution from the Combustion
  of Fossil Fuels (kilograms of emission per TJ of
  energy consumed)

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Combined Cycle

• Combines gas turbine and steam turbine.
• Exhaust energy from gas section used in steam
  system.
• High thermal efficiency.
• Small plants combined.

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Gasification

• Breaks down coal into basic chemical
  constituents.
• Coal is exposed to hot steam and controlled
  amounts of air or oxygen under high temperature
  and pressures.
• Carbon molecules in coal break apart, setting off
  chemical reactions that produce syn gas and other
  gaseous compounds.
• Integrated gasification combined-cycle (IGCC)
• Syn gas is burned in a combustion turbine which
  drives an electric generator.
• The exhaust gases are used to heat steam.

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Carbon Sequestration

• It is a family of methods for capturing and
  permanently isolating gases that could contribute
  to global climate change.
• CARBON CAPTURE
• Pre-combustion capture
• Post-combustion capture
• Oxyfuel technologies. 
• CARBON DIOXIDE SEQUESTRATION
• Industrial use of CO2 in plastics and other
  chemical industries
• Inorganic sequestration as carbonates
• Biological conversion to fuel
• Geological sequestration, in salt domes, or coal
  beds
• Injection into active oil wells
• Injection into exhausted gas or oil wells
• Ocean disposal

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Natural Gas

• The world had around 5500 trillion cubic meters
  at the end of 2003.

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• Why Natural Gas?
• Cleaner fuel, has low carbon/hydrogen ratio hence
  less carbon dioxide emission.
• Has a distinct hydrogen-rich molecular structure,
  hence supply hydrogen for future technologies
  like fuel cells.

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Methane Hydratethe gas resource of the future

• It is a compound of water and methane
• Forms under pressure at cold temperatures.
• Potential significant source of natural gas.
• Large volumes of hydrate based natural gas found
  on Alaska's North Slope.
• Natural gas potential of methane hydrate approach
  400 million trillion cubic feet.

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Atmosphere and Climate Change
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Figure 19.6
HEAT EXCHANGE WITHIN EARTH SYSTEMS
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The Greenhouse Effect
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Reducing the Impact of Global Warming
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Fuel Switching
Substitute 1400 natural gas electric plants for
an equal number of coal-fired facilities
Photo by J.C. Willett (U.S. Geological Survey).
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Nuclear Electricity
Triple the worlds nuclear electricity capacity
by 2055
Graphic courtesy of NRC
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Nuclear Power - energy from splitting Uranium
atoms

• Nuclear power is generated using Uranium, which
  is a metal mined in various parts of the world.
• Nuclear power produces around 11 of the world's
  energy needs, and produces huge amounts of energy
  from small amounts of fuel, without pollution.

electronicsdesigninfo.blogspot.com
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Advantages of using nuclear power
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disadvantages
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Solar Electricity
Install 20,000 square kilometers for dedicated
use by 2054
Photos courtesy of DOE Photovoltaics Program
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Solar power

• Most of the Earth's energy comes from the sun
• Solar power is energy from the sun
• There are two main ways that we use the Sun's
  energy
• 1. Solar Cells
• 2. Solar water heating

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Why Use Solar power?

• Advantages
• Solar energy is free - no fuel, no waste or
  pollution.
• In sunny countries, easy to use in remote places
• Good for low-power uses such as solar powered
  garden lights and battery chargers
• Disadvantages
• Doesn't work at night.
• Very expensive to build solar power stations.
• Can be unreliable unless you're in a very sunny
  place
• Solar energy is renewable because the sun is
  always there

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Wind Electricity
Install 1 million 2 MW windmills to replace
coal-based electricity, OR Use 2 million
windmills to produce hydrogen fuel
Photo courtesy of DOE
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Wind power

• Wind power also comes from the sun winds blow
  because the Sun warms our atmosphere. Warm air
  tends to rise, and winds are due to other air
  moving in to replace it.
• The wind blows the propeller round, which
• turns a generator to produce electricity
• We tend to build many of these towers together,
  to make a "wind farm" and produce more
  electricity.
• The more towers, the more wind, and the larger
  the propellers, the more electricity we can make

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Why use wind power?

• Advantages
• Wind is free.
• Produces no waste or greenhouse gases.
• The land beneath can usually still be used for
  farming.
• Wind farms can be tourist attractions.
• A good method of supplying energy to remote
  areas
• Disadvantages
• The wind is not always predictable - some days
  have no wind.
• Suitable areas for wind farms are often near the
  coast, where land is expensive.
• Some people feel that covering the landscape with
  these towers is ugly
• Can kill birds.
• Can affect television reception if you live
  nearby.
• Can be noisy.
•  
• Wind power is renewable. Winds will keep on
  blowing.

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Hydro-electric power

• Hydro-electric power is generated from falling
  water. Nowadays there are many hydro-electric
  power stations, providing around 20 of the
  world's electricity.
• How it works
• A dam is built to trap water, usually in a river
  valley.
• Water is allowed to flow through tunnels in the
  dam, to turn turbines
• and thus drive generators to produce electricity.
  

(http//www.wvic.com/hydro-works.htm) 
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Why use Hydro-electric power?
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Disadvantages
Hydro-electric power is renewable. The Sun
provides the water by evaporation from the sea,
and will continue to do it.
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Tidal power - energy from the sea

• How it works Tidal Barrages
• These work rather like a hydro-electric scheme
• A huge dam (called a "barrage") is built across a
  river estuary. When the tide goes in and out, the
  water flows through tunnels in the dam.
• The ebb and flow of the tides can be used to turn
  a turbine.

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Advantages of tidal power
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Disadvantages of tidal power

• A barrage across an estuary is very expensive to
  build, and affects a very wide area. - the
  environment and birds. There are few suitable
  sites for tidal barrages.
• Only provides power for around 10 hours each day,
  when the tide is actually moving in or out.
• Tidal energy is renewable. The tides will
  continue to ebb and flow, and the energy is there
  for free.

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Biofuels Biomass
Scale up current global ethanol production by 30
times
Photo courtesy of NREL
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Biomass - energy from organic materials

• Sugar cane can be used to make alcohol, which can
  be burned to generate power
• Other solid wastes, can be burned to provide
  heat, or used to make steam for a power station
• We can use rubbish, animal manure, woodchips,
  seaweed, corn stalks and other waste

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• Advantages
• It makes sense to use waste materials where we
  can.
• The fuel tends to be cheap.
• Less demand on the Earth's resources.
•  
• Disadvantages
• Collecting the waste in sufficient quantities can
  be difficult.
• We burn the fuel, so it makes pollution.
• Some waste materials are not available all year
  round.
• Biomass is renewable, as we're going to carry on
  making waste products. We can always plant and
  grow more sugar cane and more trees, so those are
  renewable too.

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Geothermal Energy is energy from heat inside the
Earth.

• How it works
• Hot rocks underground heat water to produce
  steam. We drill holes down to the hot region
  steam comes up, is purified and used to drive
  turbines, which drive generators to make
  electricity.
• Geothermal energy is an important resource in
  volcanically active places such as Iceland and
  New Zealand.

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Advantages
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disadvantages
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Energy Storage Systems
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Importance of Energy Storage Systems...

• Thrust for Renewable Energy sources
• Variable outputs
• new technologies and devices?

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Different Types of Energy Storage Systems

• Mechanical Energy Storage.
• Magnetic Energy Storage.
• Thermal Energy Storage.
• Chemical Energy Storage.

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• The path to the future is neither as rosy as
  some people hope nor as thorny as others fear,
  but depends on how effectively we pick out the
  weeds and nurture the bush as we walk